Vehicle Alternator Control for Idle Hunting Suppression
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Solution Overview
Problem
Existing electric power generation control systems for vehicle alternators fail to adequately suppress the hunting phenomenon during engine idle, leading to rotation speed fluctuations and voltage variations in storage batteries, which cause headlamp flicker and inefficient energy management.
Innovation Solution
An electric power generation control apparatus with an exciting current control unit, rotation speed detection unit, output voltage detection unit, and hunting suppression control unit that performs PWM control to adjust the output voltage of the vehicle alternator, maintaining it near the storage battery's opening voltage to reduce polarization and prevent battery discharge, while ensuring constant torque and current control when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the exciting current of the vehicle alternator is gradually increased to suppress rapid increase of electric power torque, then the rotation speed decrease of internal combustion engine is prevented, but the hunting phenomenon during engine idle cannot be adequately suppressed
Solution Approach 1:
The patent changes the control parameter from exciting current to output voltage. By directly controlling the output voltage of the alternator, the system can more effectively suppress hunting phenomenon during engine idle while maintaining rotation speed stability. This parameter change allows for better responsiveness and control precision in the critical idle speed range.
Solution Approach 2:
The patent implements a feedback control mechanism where the output voltage is detected and fed back to the control unit. The control unit adjusts the exciting current based on the detected output voltage to maintain it at a target value, thereby suppressing hunting phenomenon. This closed-loop feedback ensures stable rotation speed while effectively preventing alternator torque fluctuations.
2Stability of the object's composition
If the limit value of exciting current is set to prevent unstable rotation speed, then rotation speed stability is improved, but voltage fluctuation occurs in storage battery causing headlamp flicker
Solution Approach 1:
The patent uses output voltage feedback control to maintain the alternator output voltage at a target value that is higher than the storage battery voltage. This feedback mechanism prevents voltage fluctuations in the storage battery by ensuring the alternator continuously provides stable charging voltage, thereby eliminating headlamp flicker while maintaining rotation speed stability.
Solution Approach 2:
The patent sets the target output voltage to be preliminarily determined as higher than the storage battery voltage. This preliminary voltage setting ensures that the alternator output is always sufficient to charge the battery and stabilize the electrical system before any voltage fluctuation can occur, preventing headlamp flicker proactively.
3Stability of the object's composition
If the adjustment voltage is changed according to engine rotation speed to suppress hunting, then hunting phenomenon is suppressed, but adjustment timing becomes difficult and rotation speed changes occur at impertinent timing
Solution Approach 1:
The patent uses real-time feedback of the output voltage to determine when adjustment is needed, rather than relying on pre-set timing based on engine rotation speed. The control unit continuously monitors the output voltage and adjusts the exciting current only when the voltage deviates from the target value, eliminating the complexity of timing adjustment while effectively suppressing hunting phenomenon.
Solution Approach 2:
The control system automatically adjusts itself based on the detected output voltage without requiring external timing inputs or complex scheduling. The system serves itself by using its own output voltage measurement as the trigger for adjustment, making the control timing self-determined and eliminating the difficulty of synchronizing with engine rotation speed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively suppresses the hunting phenomenon, stabilizes engine rotation speed, prevents headlamp flicker, and optimizes energy management by maintaining the output voltage near the battery's opening voltage, thereby reducing battery discharge and voltage fluctuations.
Implementation Method 1
an alternator 2, which is driven by an internal combustion engine 100, generates an electrical energy
Implementation Method 2
an exciting current which flows in an exciting coil 220 of the vehicle alternator 2
Data Source
AI summary
An electric power generation control apparatus for a vehicle alternator mounted on a motor vehicle performs one of a constant output voltage control a constant torque control and a constant exciting current control in order to suppress a hunting phenomenon of the vehicle alternator. First of all, the electric power generation control apparatus performs the constant output voltage control when a rotation speed is within an idling rotation speed range or a periodic change of the rotation speed is not less than a predetermined value. After completion of the constant output voltage control, when judging that the idle hunting phenomenon is not adequately suppressed, the electric power generation control apparatus performs one of the constant torque control and the constant exciting current control.